Total and Labile Phosphorus Concentrations as Influenced by Riparian Buffer Soil Properties

Area of Science:

• Environmental Science
• Soil Science
• Ecology

Background:

• Riparian buffers can contribute phosphorus (P) to streams, especially during erosion.
• Existing tools for assessing P loss risk from buffers could be enhanced by incorporating soil and landscape variables.

Purpose of the Study:

• To determine if soil properties can predict total and labile P concentrations in a riparian buffer.
• To quantify the spatial dependence of P and related soil properties within the buffer.

Main Methods:

• Soil samples were collected from a 10-ha riparian buffer in Vermont to a depth of 60 cm using a grid design.
• Measurements included total P (TP), plant-available P (Modified Morgan extraction), pH, soil organic matter (SOM), soil texture, and select cations.
• Geospatial analyses were used to assess spatial dependence.

Main Results:

• TP and plant-available P varied widely, with significant differences between soil series (alluvial/glaciolacustrine vs. glacial till).
• While plant-available P showed weak correlations with soil properties, labile P fractions were predictable by SOM.
• Strong spatial dependence was observed for P and related soil properties.

Conclusions:

• Soil genesis significantly influences P availability in riparian buffers.
• Soil organic matter is a key predictor of labile P fractions.
• Site-specific evaluations are recommended for assessing P loss risk in riparian buffers.